The present invention relates generally to interventional catheters, and more particularly to a balloon catheter configured for use in an intravascular medical procedure in a stenosed blood vessel.
The treatment of an occluded region of a patient's vasculature commonly includes a percutaneous transluminal interventional procedure such as inflating a catheter balloon and/or implanting a stent inside the blood vessel at the site of the stenosis. For example, in balloon angioplasty, the catheter balloon is positioned across the lesion and inflated with fluid one or more times to a predetermined size at relatively high pressures (e.g. greater than 8 atmospheres) so that the stenosis is compressed against the arterial wall and the wall expanded to clear the passageway. Physicians frequently implant a stent inside the blood vessel at the site of the lesion. Stents may also be used to repair vessels having an intimal flap or dissection or to generally strengthen a weakened section of a vessel. Stents are usually delivered to a desired location within the blood vessel in a contracted condition, and expanded to a larger diameter by release of a radially restraining force (for self-expanding stents) and/or by expansion of the balloon (for balloon expandable stents). The delivery catheter is withdrawn and the expanded stent left implanted within the blood vessel at the site of the dilated lesion.
Such intravascular procedures may release emboli into the circulatory system, which can be extremely dangerous to the patient. Debris that is carried by the bloodstream to distal vessels of the brain may cause these cerebral vessels to occlude, resulting in a stroke, and in some cases, death. Thus, when performed in a carotid artery, an embolic protection device to capture and collect released emboli may be deployed downstream to the interventional catheter. For example, embolic protection devices in the form of filters or traps can be delivered in a collapsed configuration to a location adjacent to the interventional procedure site, radially expanded to open the mouth of the filter or trap, and after the interventional procedure has been performed, the device is collapsed for removal with the captured embolic material therein.
An essential step in effectively performing an interventional procedure is properly positioning the catheter system at a desired location within the patient's vasculature. The catheter shaft must be able to transmit force along the length of the catheter shaft to allow it to be pushed through the vasculature. However, the catheter shaft must also retain sufficient flexibility and low profile to allow it to track over a guidewire through the often tortuous, narrow vasculature. Such deliverability issues must be balanced against one another and against other performance characteristics. As a result, one design challenge has been making the procedure, including the delivery and retrieval of the components of the catheter system, as quick and easy as possible.